[talk-ph] GIST-OCHA PH Core Data Layers as shapefile

[maning sambale]

Dear everyone,

Nicolas provided some Philippine datasets from the UN GIST-OCHA
repository.   The full list and link to the shapefiles below:

> http://brainoff.com/nchavent/Web/FileTransfer/PHShape.zip

phl_airdmp_1m_iscgm.shp
phl_coasta_isl_gsi.shp
phl_contourl_naga.shp
phl_lakeresa_1m_iscgm.shp
phl_lndcvra_moaphl.shp
phl_polbnda_adm1_gsi.shp
phl_polbnda_adm2_gsi.shp
phl_polbnda_adm3_gsi.shp
phl_polbnda_adm4_gsi.shp
phl_polbndl_adm1_gsi.shp
phl_polbndl_adm2_gsi.shp
phl_polbndl_adm3_gsi.shp
phl_polbndl_adm4_gsi.shp
phl_pplp_unk.shp
phl_prtp_sea_moaphl.shp
phl_rdsl_250k_namria.shp
phl_watcrsl_rvr_gsi.shp

CRS - is GCS WGS-84 (same with OSM)

We are coordinating with the Philippine office of the Office for
Coordination of Humanitarian Affairs (OCHA) on the license and data
history.
Pending the clarification of the license, I had a brief view of the
data and compared it to our OSM datasets.  From what I saw, the
following layers can be useful in the context of OSM data and the
relief efforts (I'm not directly talking about imports).

 - phl_polbndl_adm3_gsi.shp - municipal admin boundaries
 - phl_polbndl_adm4_gsi.shp - barangay admin boundaries
 - phl_rdsl_250k_namria.shp - roads (based on the filename at 1:250K scale)
 - phl_watcrsl_rvr_gsi.shp - rivers

Some issues in the data:
1. Coordinates and datum - Although they are of the same coordinate
system and datum I have doubts if the original data was GCS WGS-84.
As point of reference here's an image of Marikina Heights Barangay
boundary (orange dash lines) over OSM roads (thin brown line).
http://farm5.static.flickr.com/4151/5104724734_055b876996_z.jpg

I'm using this as an example because I'm confident on the OSM data
around this area.  The admin boundaries in most cases should follow
the road.  http://www.openstreetmap.org/?relation=371327

I suspect this is even worse in other areas.  I'm not entirely sure if
this is a datum shift issue. If you have the time please investigate.
If we can rectify this, then some of it maybe useful.

2. Roads - Comprehensive in some areas but inconsistent in coverage
and, assuming it is 1:250K scale, low res for OSM purpose.  Image
below (blue is UN data, brown is OSM):
http://farm5.static.flickr.com/4130/5104142239_d9ed4300cb_z.jpg

3. Comprehensive coverage but also suffers with the low res and
projection issue.
http://farm2.static.flickr.com/1356/5104747190_a51aebf0e7_z.jpg
http://farm5.static.flickr.com/4130/5104150969_7662edd63d_z.jpg

Should we import this data to OSM? I DON'T THIS SO, both in terms of
data quality and our previous discussion with imports in general.

http://lists.openstreetmap.org/pipermail/talk-ph/2010-September/002563.html
http://wiki.openstreetmap.org/wiki/WikiProject_Philippines/Data_import#Guidelines_for_OSM-PH_bulk_data_import

However, I do see the value of the UN's datasets on the following grounds:
1. It is difficult to survey admin boundaries.  If we can solve the
projection problem, then, perhaps we can use the data as "guide" to
adding admin boundaries.
2. The rivers data can be used to add river names and  assess which
areas we can add more rivers with Landsat.
3. The road data can be used for planning further ground surveys.

Maybe we can setup a WMS which we can load as an underlay in the OSM
editors?  Finally, I think we should initiate a communication with the
UN-OCHA Philippine Office in order to improve their existing datasets.


On Thu, Oct 21, 2010 at 5:26 PM, nicolas chavent
<nicolas.chavent at gmail.com> wrote:
> Maning
>
> GIST-OCHA PH Core Data Layers as shapefile at
> http://brainoff.com/nchavent/Web/FileTransfer/PHShape.zip
> Looking for clarity on the licencing scheme associated to this set of data
>
> Hyper best
> Nicolas
>
> --
> Nicolas Chavent
> Humanitarian OpenStreetMap Team
> http://wiki.openstreetmap.org/wiki/WikiProject_Haiti
> Mobile (Haiti): +509 389 583 05
> Landline (FRA): +33 2 97 26 23 08
> Email: nicolas.chavent at gmail.com
> Skype: c_nicolas
> Twitter: nicolas_chavent
>
>



-- 
cheers,
maning
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"Freedom is still the most radical idea of all" -N.Branden
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